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About SteveBz

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    Proto Star

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    West Sussex
  1. I was thinking of averaging over several days so that rotation of the sun removed any granulation. In the meantime you could download some from nasa/soho, after all, a sphere is a sphere is a sphere. But you might have to do something about aligning histograms - maybe. I haven't done any of this yet, but here's a flattened picture from soho. Additionally, I'd quite like to stretch the histogram from the top creating greater contrast and uncurl it by dividing by sin(theta) so that the edge artifacts don't look edge on. Good luck, Steve
  2. OK, tx. I'll test it out.
  3. Should I repost in imaging? Maybe one of the admins can move it.
  4. I was thinking that you'd be better off averaging over a number of days to avoid the natural granularity of the sun becoming a factor. Is that not necessary? Regards Steve.
  5. Hi Guys, Does anyone use solar flats to flatten their solar images? I'm guessing now would be the time to make them. Do you have a complete workflow? Regards, Steve.
  6. Hi Graeme, I'd never seen the stretch function before, great. It's exactly what I want. I'm not sure what you mean by colour cast, but I can do the stretch by channel and that means we don't have the bright blue effect. But what about the gradient? Is there a gradient tool in GIMP? How do I deal with that? So now I can just see it, I'm sure some more lights will help. Regards, Steve.
  7. Hi Graeme, I thought I knew this stuff, but there is so much in your answer that eludes me. What does "pinned to the left" mean? I try to take images for as long as I can, while not swamping the image with light pollution. Like this: Maybe this is a similar point. How should I measure this? OK, I did try ISO800 the day before, but without much success. I'll try again. It looks like Sunday may be a clear night. You're saying I shouldn't truncate the image too severely. Here is my calibrated and stacked image: You can just make out the galaxy. I use the ink dropper tool to choose the darkest area of the stacked and calibrated image to create a new layer which I subtract from the noisy layer (eg the one that looks like the one above). So if it's sort of light blue colour like this (it looks more than 21:21:21): Giving this: Then I again use the dropper to create a white-ish layer like this: To create this: Which is what I posted. What does "reduced" mean? Thanks for your help Graham, Regards Steve.
  8. Thank you for plate-solving these. I do have a spare Canon 350D, that I could get modified. I'll think about that. Regards Steve.
  9. Hi Guys, Here are two calibrated single shots of IC5146 (Cyg) or NGC 6946 (Cen). IC5146 (Cyg) is the Cocoon Nebula and NGC 6946 (Cen) is a galaxy. If I amplify the images I can just make something out, but they seem amazingly dim. Processing is as follows: 200 mm Newtonian (f/5) with PHD2 guiding and Nikon DSLR D5000. 1 NGC 6946) or 2 (IC 5146) light frames of 240 secs @ISO 1600. 61 x BIAS (ISO1600). 37 x FLAT (ISO1600). No darks. Then Noise subtraction and white balance using gimp. But at no point can I see a nebula or a galaxy, unless I really ramp up the signal amplification, when everything is noise. What's gone wrong? Is there just too much light pollution in West Sussex? The signal was sooo... faint, I spent a long time just working out if I'd even got the right location, it was just plate-solving against the wonderful Henry Draper catalogue that convinced me. Let me know what you think. Regards, Steve.
  10. Are you on Windows or Linux? On linux, it's just treated as a webcam as in /dev/video0 etc. On windows I don't know, but I guess it's the same. It was probably made for a microscope and converted for a telescope. It's not terribly sensitive, but you can use it for a guidescope on brighter stars. You can also get planetary images, although they're not great. I upgraded to a QHY5 which is much much better. You can also use a zwo asi120mm for 100 odd quid off alibaba express. Good luck, Steve.
  11. Just found a Celestron manual with 9 settings. Maybe I just need to test it.
  12. Have you done this? You've got quite a lot of Newtonians. Is there much difference between them? I have a 114 mm and 200 mm and the difference is so huge I only use the smaller one for outreach and testing. Steve.
  13. As I read it, it's slew until I tell you to stop. I've attached the full protocol, but as I understand it, the first three parameters are "fixed rate slew", "positive or negative" and "RA/DEC", not necessarily in that order. Then you give it a rate. Like this: The text says: For fixed rates, simply use a value from 1-9 (or 0 to stop) to mimic the equivalent hand control rates. Note: in most configurations, issuing the slew commands will override (or conflict with) the tracking mode of the mount. Hence it is always best to disable tracking first using the Tracking Commands, issue the slew command, and then re-enable tracking. The main exception to this is when tracking equatorially - the fixed rate slews at 1 or 2 will not override tracking. This can be useful to simulate auto-guiding. But the rates are: So there seems to be a tension between the two definitions over what happens for zero. I may just test it, but it's hard to measure rates like .5x and 1x, without a vernier calliper. Regards Steve synscanserialcommunicationprotocol_version33.pdf
  14. Hi Dr Juju, You said that before, and I'd love to. It just a long process. I think you saw my previous attempt, but it's on pause until I can get something working to look upwards. Then I'll have some spare time. Regards, Steve
  15. Hi Guys, I'm trying to automate my scope and I've upgraded from a Skywatcher Enhanced handset controlled by an Arduino to a goto Synscan controlled by a Raspberry Pi with Python. I have control of the handset now, but I'm having difficulty interpreting the manual. It says send the slew command (eg 'P' +chr(2)+chr(16)+chr(36)+chr(rate))or something like that. Rate is supposed to be 1-9 or zero for stop, but there are 10 rates with 0 =. 5x. How does that work? Does it mean 0.5x is not available? I'm a bit thrown. Regards, Steve.
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